From: Jakub Kicinski <kuba@kernel.org>
To: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net, roopa@nvidia.com,
Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: [PATCH net-next] net: bridge: mcast: fix unused br var when lockdep isn't defined
Date: Tue, 8 Sep 2020 09:00:49 -0700 [thread overview]
Message-ID: <20200908090049.7e528e7f@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <20200908071713.916165-1-nikolay@cumulusnetworks.com>
On Tue, 8 Sep 2020 10:17:13 +0300 Nikolay Aleksandrov wrote:
> Stephen reported the following warning:
> net/bridge/br_multicast.c: In function 'br_multicast_find_port':
> net/bridge/br_multicast.c:1818:21: warning: unused variable 'br' [-Wunused-variable]
> 1818 | struct net_bridge *br = mp->br;
> | ^~
>
> It happens due to bridge's mlock_dereference() when lockdep isn't defined.
> Silence the warning by annotating the variable as __maybe_unused.
>
> Fixes: 0436862e417e ("net: bridge: mcast: support for IGMPv3/MLDv2 ALLOW_NEW_SOURCES report")
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
> ---
> net/bridge/br_multicast.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
> index b83f11228948..33adf44ef7ec 100644
> --- a/net/bridge/br_multicast.c
> +++ b/net/bridge/br_multicast.c
> @@ -1814,8 +1814,8 @@ br_multicast_find_port(struct net_bridge_mdb_entry *mp,
> struct net_bridge_port *p,
> const unsigned char *src)
> {
> + struct net_bridge *br __maybe_unused = mp->br;
> struct net_bridge_port_group *pg;
> - struct net_bridge *br = mp->br;
>
> for (pg = mlock_dereference(mp->ports, br);
> pg;
That's a lazy fix :( Is everyone using lockdep annotations going to
sprinkle __maybe_unused throughout the code? Macros should also always
evaluate their arguments.
next prev parent reply other threads:[~2020-09-08 16:20 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-08 3:00 linux-next: build warning after merge of the net-next tree Stephen Rothwell
2020-09-08 3:49 ` Jakub Kicinski
2020-09-08 7:17 ` [PATCH net-next] net: bridge: mcast: fix unused br var when lockdep isn't defined Nikolay Aleksandrov
2020-09-08 16:00 ` Jakub Kicinski [this message]
2020-09-08 16:09 ` nikolay
2020-09-08 17:36 ` [PATCH net-next] rcu: prevent RCU_LOCKDEP_WARN() from swallowing the condition Jakub Kicinski
2020-09-08 18:15 ` nikolay
2020-09-09 0:27 ` Jakub Kicinski
2020-09-14 20:21 ` Joel Fernandes
2020-09-14 22:47 ` Jakub Kicinski
2020-09-15 0:20 ` Paul E. McKenney
2020-09-15 0:30 ` Jakub Kicinski
2020-09-15 17:02 ` Paul E. McKenney
2020-09-15 1:34 ` Joel Fernandes
2020-09-09 3:12 ` David Miller
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